CSS Layers

Stacking Elements in Layers Using z-index Property

Usually HTML pages are considered two-dimensional, because text, images and other elements are arranged on the page without overlapping. However, in addition to their horizontal and vertical positions, boxes can be stacked along the z-axis as well i.e. one on top of the other by using the CSS z-index property. This property specifies the stack level of a box whose position value is one of absolute, fixed, or relative.

The z-axis position of each layer is expressed as an integer representing the stacking order for rendering. An element with a larger z-index overlaps an element with a lower one.

A z-index property can help you to create more complex webpage layouts. Following is the example which shows how to create layers in CSS.

Example

.box {
    position: absolute;
    left: 10px;
    top: 20px;
    z-index: 2;
}